S/steel extractors are the way to go (either lukey or pacemaker) as you get alot longer warranty and they dont seem to crack like standard ones.

The standard for mufflers are absolute pieces of poo (extremely restrictive!) for a decent hi flow cat youd be looking around the $250 mark (mine were 350 each and i hadta buy 2 of em!).

i wouldnt go any larger than say 2 1/4" - 2.5", exhaust places recomend goin no larger than that unless your producing more than 300+ horsepower at the flywheel. (even a 2.5" system is good for upto 500hp!).

and if you want a decent note i suggest you loose the muffler all together and put on a hotdog type resonator, youll get alot nicer sound! (and theyre a shitload cheaper than good mufflers!).
so for a decent system expect to pay.

definately go pacemaker extractors, but with the exhaust go as big as you can afford, with the cat as big as the rest, and get the best quality mufflers you can afford too. Everyone thinks you need some back pressure in your exhaust but thats not true, any back pressure is robbing your power!! id reckomend a 3" mild steel (keep cost down) with s/s mufflers and 3" hi flow cat